Roger william wallace



UNITED STATES PATENT OFFICE.

ROGER WVILLIAM WALLACE, OF LONDON, ENGLAND, ASSIGNOR TO THEELECTRO-METALLURGICAL COMPANY, LIMITED, OE SAME PLACE.

CRUCIBLE AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 585,993, dated July 6,1897. Application filed June 13, 1896. Serial No. 595,480. (No model.)

To all whom it may concern.-

Be it known that I, ROGER WILLIAM \VAL- LACE, a citizen of England, anda resident of London, England, have invented certain new and usefulImprovements in Crucibles and Processes of Making the Same, of which thethe following is a full, clear, and exact description.

This invention relates to improvements in the fusion of chromium andsimilar metals and to the manufacture of their alloys with the usualmetals.

To facilitate the following description, it may be said at once that thebodies herein referred to as similar to chromium are molyb-. denum,tungsten, uranium, or alloys of these metals, either with one another orwith chromium; and it should be fully understood that when chromium isspoken of what is said is to be understood of the above-designatedmetals or their alloys.

The fusion of chromium requires the use of excessively-hightemperatures, and when this fusion is effected in ordinary crucibles,able to resist the temperatures employed, the chromium is contaminatedby the Very matter which constitutes the crucible. Thus it is that acrucible or receptacle of carbon carburizes the metal and imparts to itproperties which it is important to guard against. To avoid difficultyfrom this source, the crucibles or receptacles are,in accordance withthe present invention, lined with oXid of chromium. To effect thislining, the following procedure is employed: In a suitable crucible orreceptacle borax, cryolite, sodium chlorid, calcium fluoride, or amixture of these bodies is melted with an addition of oxid of chromium,which rests in suspension in the fused or molten mass. This done, theinterior surface of the crucible which is to be lined (and which may beheated or not) is coated with the molten mass by any suitable process,or, in particular, by successively inclining the crucible in alldirections, so that the fused mass covers over the whole interiorsurface of the crucible and thereby forms a protecting coat.

It is to be noted that, the object of this invention being to obtainalloys of chromium, 85c. containing no additional metal than that whichserves as the base of the alloy, it is not admissible to employ chromeores, as has been proposed heretofore for making linings of furnaces,and which contain iron oXid and silica. I utilize by my invention theordinary graphite retorts by lining the same expeditiously at the momentof utilization.

The method of lining just described, with reference to the fusion, isapplicable without modification to the preparation of crucibles orreceptacles for the production of alloys of chromium with the usualmetals.

I claim as my invention or discovery- 1. The described improvement inthe manufacture of crucibles for fusion of chromium and similar metalsand for production of alloys thereof with other metals, said improvementconsisting in lining the crucible with the oXid of the correspondingmetal by fusing a flux, such as hora-X, with addition of an oXid of thedesired metal until the oxid is held in suspension in the flux, andthen, by agitating the mass while the same hardens, forming a coatingthereof upon the interior of the crucible, as set forth.

2. A crucible provided with an adherent interior coating of oxid ofchromium free fro-m other metallic base, substantially as described.

23. A crucible with an adherent interior coating of oXid of chromiumfree from other metallic base and a suitable flux, substantially asdescribed.

In testimony whereof I have signed this specification in the presence oftwo subscribin g witnesses.

ROGER IVILLIAM IVALLACE.

\Vitnesses:

EDWARD P. MAoLEAN, EDWARD BARBARY.

